Automatic fill-up and cementing devices for well pipes



April 28, 1964 T. E. ALEXANDER ETAL 3,

AUTOMATIC FILL-UP AND CEMENTING DEVICES FOR mam. PIPES HTTORNEVJ April28, 1964 r. E. ALEXANDER ETAL ,7

AUTOMATIC FILL-UP AND CEMENTING DEVICES FOR WELL PIPES Filed Aug. 30,1961 2 Sheets-Sheet 2 Tho/27am" f. A/exan a e/ Way/76% A/e/Jon INVENTORSATTO/P/VEVJ United States Patent 3,130,789 AUTOMATIC FILL-UP ANDCEMENTING DEVICES FOR WELL PIPES Thomas E. Alexander, Houston, and WayneF. Nelson,

Waxahachie, Tex., assignors to Koehring Company,

Waxahachie, Tern, a corporation Filed Aug. 30, 1961, Ser. No. 134,932Claims. (Cl. 166224) This invention relates to new and usefulimprovements in automatic fill-up and cementing devices for well pipes.

In well completion operations, it has been the practice to fill a wellpipe, which is to be ultimately cemented in final position, as .suchpipe is being lowered and various types of automatic fill-up andcementing devices have been in general use. Recently, the so-calledtubingless completions, which eliminate the use of a well casing byutilizing the well tubing as the casing, are coming into more widespreaduse and because the well tubing is of considerably less diameter thanthe well casing heretofore employed, certain new problems are presentedin connection with automatic fill-up and subsequent cementing of thesmaller size well pipe.

For example, in tubingless completions, it is desirable to pump thecement downwardly at the highest possible rate so as to displace the mudin the annulus and the cement outlet should be completely unrestricted;also, after cementing is completed, it is essential that there be animmediate and positive closing of the back check or pressure valve toassure that there be no back leakage of cement because even a slightleakage will fill a considerable length of the smaller diameter pipe.Additionally, automatic fill-up of the pipe is desirable but at the sametime, efiective protection against possible blow-out of the Well duringlowering of the pipe should be provided.

Conventional fill-up and cementing devices designed primarily for usewith the larger diameter well casing have been found inadequate for usein the tubingless completion field.

It is, therefore, one object of this invention to provide an improvedfill-up and cementing device which is primarily adapted for use inrunning and cementing small diameter pipe, such as well tubing, within awell bore but which may, if desired, be employed with well casing orlarger diameter pipe.

An important object is to provide a device, of the character described,having means for allowing a controlled or regulated fill of the pipeduring lowering and which incorporates a full opening cementing valve,whereby maximum rate of cement pumping may occur; said valve beingconstructed to immediately and positively seal as a backpressure valvewhen the cementing operation is complete to prevent any reverse leakageof the cement into the well pipe.

Another object is to provide a device, of the character described,wherein a predetermined size orifice perrnits automatic controlled fillof the pipe during lowering and also wherein a normally open back checkvalve is associated with the orifice in such manner that anypredetermined excessive entry of fluid through the orifice, such asmight ultimately result in a blow-out, will atiect the back check valveand automatically move said valve to closed position to thereby provideprotection against blow-out.

LA further object is to provide a fill-up and cementing device, of thecharacter described, wherein the back check valve which functions toprovide blow-out protection during lowering of the well pipe also actsas a cementing valve during a subsequent cementing operation; said valvebeing of an improved construction to assure a positive and leak-proofseal when in its seated position to prevent back flow of cement or otherfluids into the well pipe.

3,130,789 Patented Apr. 28, 1964 A particular object is to provide afill-up device having a valve element mounted therein, which element hasits opposite sides exposed to the same annulus pressure and which isnormally held in position permitting flow into the well pipe by areleasable means; a predetermined change in the differential pressuresacting on opposite sides of the valve element, which change is caused bya predetermined increase in velocity of flow of fluid entering the pipe,resulting in release of said releasable means to automatically move thevalve to a position closing said pipe to thereby protect the wellagainst blow-out.

A still further object is to provide a device, of the characterdescribed, wherein a predetermined size orifice controls the filling ofthe well pipe and wherein a holding means requiring a predeterminedforce for release maintains the pipe closure valve in open position; thesize of the orifice being so related to the force required to releasethe valve holding means that under normal flow of fluid into the pipefor filling purposes, the valve remains open but under excessive flowconditions the holding means is automatically released to move the valveto a position shutting off further entry of fluid into said pipe.

The construction designed to carry out the invention will be hereinafterdescribed, together with other features thereof.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawingsforming a part thereof, wherein an example of the invention is shown,and wherein:

FIGURE 1 is a transverse vertical sectional view of a fill-up andcementing device, constructed in accordance with the invention andshowing the parts thereof in the position during lowering of the pipeand normal controlled filling of said pipe;

FIGURE 2 is a similar view, illustrating the valve element of the devicein its lowered position which it assumes during the cementing operation;

FIGURE 3 is a similar view, illustrating the valve element of the devicein its upper position closing the lower end of the pipe againstback-flow of fluid into the pipe;

FIGURE 4 is a horizontal cross-sectional view taken on the line 4-4 ofFIGURE 1;

FIGURE 5 is a horizontal cross-sectional view taken on the line 55 ofFIGURE 2;

FIGURE 6 is a schematic or diagrammatic view of a well bore showing thewell pipe having the improved device at its lower end being lowered intothe well bore during which time a controlled filling of the well pipewith liquid from the annulus is accomplished;

'FIGURE 7 is a view similar to FIGURE 6 illustrating the position of theparts during the introduction of cement into the well bore; and

FIGURE 8 is a similar view showing the valve element of the device inits back-check position preventing a reverse flow of fluid into thelower end of the pipe.

In the drawings, the numeral 10 designates a cylindrical tubular bodyhaving a bore 11 extending entirely therethrough. The lower end of thebore of the body is closed by a plug 12 which is preferably threadedinto said lower end. An annular inclined valve seat 13 is provided inthe upper portion of the body and above the valve seat a threaded box 14is formed whereby the well pipe or tubing T may be connected therewithin the usual manner. Spaced below the annular valve seat 13 is a fillingport 15 which is constructed of a predetermined size and which willpermit an inflow of fluid from the area outside of the body into thebore and then upwardly into the well pipe or tubing T, as will behereinafter explained. Spaced downwardly from the filling port ororifice 15 are a plurality of cementing ports 16, and as is clearlyshown in FIGURE 2, a number of these ports are provided. With small pipethe combined cross-sectional area of the cementing ports should be atleast as great as the cross-sectional area of the bore 31 of the wellpipe or tubing string T, whereby when cement is pumped downwardlythrough said well pipe, the cementing ports do not form a restriction tothe flow of cement outwardly into the area around the body 10. Withlarge pipe a port area less than the crosssectional area of the pipe maybe adequate as cement will be introduced to the pipe from smallersurface piping. In any case the port area should not be such as to causea restriction. Nearer the lower portion of the body are a plurality offluid equalizing openings 17 so that pressures inside and outside of thebody may equalize in the lower portion thereof above the plug element12.

A valve element generally indicated at A is slideable within the bore 11of the body and, as will be explained, is adapted to coact with thecementing ports 16 and also with the filling orifice or port 15. Thevalve element includes a main valve body 18 having a closed upper endwhich is preferably substantially fiat throughout its major area. Theouter peripheral edge portion of said upper surface is inclined orbeveled at 19 to form a valve sealing surface which under certainconditions is engageable with the internal valve seat 13 within theupper end of the body. Immediately below the sealing surface 19, thevalve body has a pair of O-rings 20 mounted within suitable annularrecesses 21 and said O-rings seal between the external surface of thevalve body 18 and the bore 11 of the body. The lower end of the valvebody is reduced to provide a depending annular skirt 22 and at theintersection of said skirt with the main body an external annularshoulder 23 is formed. A coiled spring 24 is preferably confined withinthe lower portion of the body with its upper end in engagement with theannular shoulder 23 and its lower end engaged with the closure plug 12.The spring exerts its force to constantly urge the valve element Aupwardly within the body. It might be noted that although it ispreferable to employ the spring 24, it has been found that such springcould be omitted.

The valve element A is normally retained within the body in the positionshown in FIGURE 1 by a frangible shear pin 25, said pin extendingthrough the wall of the body and into a recess 26 in the exteriorsurface of the valve element. As will be explained in detail, thestrength of the shear pin 25 is related to the size of the fill port andwhen the shear pin is connected with the valve element A (FIGURE 1),said valve element overlies the cementing ports 16 to close the same.The O-rings on the valve element seal with the wall of the body bore 11and prevent any How of fluid from the area above the valve elementoutwardly through the ports 16. The length of the valve element is suchthat when in the position of FIGURE 1, its upper end is below the fillport 15 while its lower end is above the equalizing ports 17; obviously,the upper end of the valve element is spaced downwardly from theinternal valve seat 13 which is provided in the upper portion of thevalve body. With such arrangement, the cementing ports 16 are closed andfluid from the area outside of the body may flow through the fillingport 15 into the well pipe or tubing string T. This same pressure mayenter the ports 17 and is present in the area below the valve element sothat, in effect, under static conditions, pressures above and below thevalve element are equalized. The coiled spring is tending to urge thevalve element upwardly but the shear pin which connects the valveelement in the position of FIGURE 1 prevents such upward motion.

The pin 25 may be sheared under one of two conditions which may occur.If a sufiicient pressure is applied to the upper end of the valveelement A, as for example by pumping cement downwardly through the wellpipe or string T, the pin 25 will be sheared which will move the valveelement A downwardly to the position shown in FIG. 2 to uncover thecementing ports. Under such condition. cement may be pumped outwardlythrough the ports 16 into the area outside of the body 10 and it isnoted that at this time the valve sealing surface 19 as well as theO-rings 20 are below the cementing ports and neither the sealing surfaceor the O-rings will be affected by the abrasive action of the cementfluid. Upon completion of a cementing operation, the coil spring 24 willmove the valve to the position shown in FIGURE 3 and in such positionthe beveled sealing surface 19 of the valve element 8 engages theinternal seat 13 to effectively close any upward flow into the wellpipe. The O-rings will assist in effecting a positive back-check seal.

The second condition under which the pin 25 may be sheared to permit amovement of the valve element A is upon a predetermined pressurediflerential occurring across the valve element. As has been noted, whenthe pipe is being lowered with the valve element A connected by theshear pin 25 and maintained in the position of FIGURE 1, fluid fromoutside the body may enter the orifice 15 and enter the well pipe. Thesame pressure may also enter the equalizing ports 17 so that undernormal filling conditions the pressures across the valve element are notgreat enough to shear the pin. There will of course be a slightly lesserpressure in the area immediately above the valve element than the staticpressure which is acting on the lower end of the element, this beingcaused by the fact that there is an upward flow into the well pipe. Thestrength of the shear pin is so related to the size of the port 15 thatunder normal filling conditions the parts will remain in the position ofFIGURE 1. However, if there is a tendency for the well to blow-out, thevelocity of flow through the control orifice 15 will be increased andthe upward velocity into the well pipe will increase accordingly tothereby result in a reduction in pressure above the valve element. Byrelating the size of the port 15 to the shear pin 25, it is possible tocause a shearing of the pin by the static pressure acting underneath thevalve element when a predeter mined pressure drop occurs above theelement. When such predetermined pressure drop occurs, the pin 25 issheared and the valve element A is moved to the position of FIGURE 3; insuch position, its sealing surface 19 engages the internal valve seat 13and the O-rings 20 seal with the wall of the bore 11 of the body abovethe filling port or orifice 15 and an effective back-check or back-flowvalve is thus provided.

Specific examples of the operative relation between the size of the port15 and the strength of the shear pin are now set forth. For instance,assuming that a 4"-20 shear screw retaining a valve element having aneffective pressure diameter of 3%" is to be sheared when 10 pound mud isflowing through the orifice at the rate of gallons per minute, then theorifice should be approximately 0.624" in diameter. Under similarcircumstances but using a "-18 shear screw, the diameter of the orificeshould be approximately 0.551".

In the operation of the improved fill-up and cementing device, referenceis made to FIGURES 6 through 8 in which the device is connected to thelower end of a tubing string T which is adapted to be lowered within awell bore W. A short section of surface casing 26 is set within the wellbore W and has the usual tubing head 27, which is shown schematicallymounted at its upper end. The head has a fluid outlet 28 controlled by asuitable valve 29 and also includes a conventional packing or seal 30which seals off the annulus between the well bore W and the tubing T.

The shear pin 25 is positioned to connect the body 10 with the valveelement A and to dispose said valve element in the position shown inFIGURE 1 and as the tubing string T is lowered the fluid, which isgenerally drilling mud from the annulus, flows through the fill-up portor orifice 15 and provides for an automatic controlled filling of thetubing string during the lowering operation. By relating the size of theorifice or port 15 to the strength of the shear pin 25, a controlled orpredetermined amount of fluid may flow into the tubing and the pressuredifferential created across the valve element A will be insufiicient toshear said pin 25. Thus, during lowering of the tubing string and withconditions normal, a predetermined amount of fluid is introduced intothe tubing to fill said tubing automatically.

In the event that the fluid within the annulus begins to enter the portor orifice at a rate which might cause a blow-out of the well, thevelocity of flow of liquid upwardly in the tubing is increased and thisincreased velocity results in a reduction in the pressure which isacting against the upper end of the valve element A. The lower end ofthe valve element, as has been explained, is constantly exposed to thestatic fluid head and when the reduction in pressure above the valveelement A is sufficient, the pressure acting below the valve elementwill shear the pin 25 and move the valve element A to the position shownin FIGURES 3 and 8. In such position, a back flow of any fluids into thetubing string T is effectively prevented because the sealing surface 19of the valve element is in engagement with the internal valve seat 13within the upper portion of the body. Also, the O-ring seals are engagedwith the bore 11 of the body in the area between the internal seat 13and the orifice or port 15 and thus such port is effectively closed. Thepressure below the valve element maintains it in its back-check sealingposition and thus positive protection against blow-out is provided.

In the event that the tubing string T is lowered to final positionwithin the well bore W without there having been any occurrence whichmight tend to cause a blowout, then the cement is pumped downwardlythrough the tubing string T in the usual manner. This is illustrated inFIGURE 7 and the pressure of such cement is applied against the upperend of the valve element A to shear the pin and move the valve elementdownwardly to the positions shown in FIGURES 2 and 7. In such positionsthe large cementing ports 16 are uncovered and the cement may be rapidlyintroduced into the annulus to displace the mud or fluid within theannulus upwardly; of course, at this time, the valve 29 in the line 28at the upper end of the annulus is opened to permit displacement of saidmud. Upon completion of the cementing operation, the reduction ofpressure in the tubing string permits the valve element A to beimmediately moved into its seated, back-check position as shown by FIG-URES 3 and 8. The upward movement of the valve to back-check position iseflected primarily by the pressure acting below the valve element andwhere the coil spring 24 is employed, such spring adds its force to thepressure to assure seating of the valve. It is noted that during thecementing operation the upper surface of the valve element A is belowthe cementing ports 16 so that the annular surface 19 and the O-rings 20are not exposed to the abrasive action of the cement. This means thatthe surface 19 and the O-rings 20 will etiectively and immediately moveinto sealing position when the valve element is moved upwardly.

From the foregoing it will be seen that a simple and effective fill-upand cementing device is provided. By controlling the size of the inletorifice or port 15, a predetermined volume of fluid from the annuluswill flow into the tubing string during the lowering operation. Undernormal conditions, the valve element A is maintained in the position ofFIGURE 1 closing the cementing ports and the shear pin 25 remainsintact. In the event of any excessive increase in velocity of the fluidflowing upwardly in the tubing, a pressure reduction occurs above thevalve element and when such reduction is to a predetermined point inaccordance with the strength of the shear pin 25, the pin is sheared andthe valve is moved upwardly to provide blow-out protection. It, on theother hand, the tubing is lowered into final position without anytendency for blow-out, the valve element has remained in the position ofFIGURE 1 with the shear pin 25 connecting the same to the body. Upon theapplication of pressure through the cement column which is to be pumpedinto the well, the pin 25 is sheared to move the valve element Adownwardly and uncover the large cementing ports which permits a rapidpumping of cement into the annulus. Upon completion of cementing, thevalve is immediately moved to its back-check or closing position, asshown in FIGURE 3, to prevent any back leakage of cement into saidtubing string. Although it has been found that a shear pin or otherfrangible means is a simple way of latching or holding the valve elementin position, other types of latches could be employed. Any latch orholding means which maintains the valve element A in its position asshown in FIGURE 1 would, of course, be related to the size of the fillport or orifice 15 so that the force required to release the valveelement for upward movement under predetermined pressure difierentialconditions may be controlled. The proper relationship between the port15 and the force required to release the valve element for movementupwardly may be predetermined and will, of course, be varied inaccordance with the particular conditions of the well in which thedevice is to be used.

The foregoing disclosure and description of the invention isillustrative and explanatory thereof and various changes in the size,shape and materials, as well as in the details of the illustratedconstruction, may be made within the scope of the appended claimswithout departing from the spirit of the invention.

What we claim is:

1. A fill-up device including, a tubular body having means forconnecting said body in a well pipe string, said body having an orificeestablishing communication between the exterior and interior thereofwhereby fluid from the annulus surrounding the body and pipe string mayflow through the orifice and into the string, a piston valve elementmounted for movement within the body and movable to a position closingflow into the pipe string, said valve element being subjected to thepressure of the fluid flowing through said orifice into the pipe string,said valve element having means coacting with said tubular body toprevent flow through said orifice when said valve element is moved tosaid position closing flow into the pipe string, releasable means fornormally holding said valve element in a position allowing flow throughthe orifice and into the pipe string, said releasable holding meansbeing released by the differential pressure caused by a predeterminedincrease in the velocity of fiow of fluid passing through said orificeto permit movement of the valve element, said diflerential pressure alsomoving the valve element to a position closing further flow into thepipe string.

2. A fill-up device including, a tubular body having means forconnecting said body in a well pipe string, said body having an orificeestablishing communication between the exterior and interior thereofwhereby fluid from the annulus surrounding the body and pipe string mayflow through the orifice and into the string, a piston valve elementslideably mounted within the bore of the tubular body and movable to anupper position closing flow into the pipe string, said valve elementhaving means coacting with said tubular body to prevent flow throughsaid orifice when said valve element is moved to said position closingflow into the pipe string, a releasable means for normally holding saidvalve element in a lowered position allowing flow through the orificeand into the pipe string, said last-named means being releasable uponthe application of a predetermined force against the valve element, theupper surface of said valve element being exposed to the pressure of thefluid flowing through the orifice and entering the string, means forexposing the lower surface of said element to the static pressure of thefluid in the annulus exteriorly of the body, a predetermined increase inthe velocity of the fluid flowing through said orifice and into the pipestring resulting in a reduction in the pressure acting against the uppersurface of the element,

whereby the pressure differential across the element creates therequired force to release the releasable holding means and to thereaftermove the valve element to an upper position closing further flow intothe pipe string.

3. A fill-up device as set forth in claim 2, wherein the releasablevalve element holding means is a shear pin.

4. A fill-up device as set forth in claim 2, together with a springmeans within the body below the valve element and exerting its force toconstantly urge the valve element toward an upper position within thebody.

5. A fill-up and cementing device including, a tubular body havingbottom closure means and having means for connecting said body in a wellpipe string, said body having an orifice located nearer its upper endand establishing communication between the annulus outside the body andstring and the interior of the body and string, said body havingcementing ports below said orifice and having equalizing openings spacedbelow said cementing ports and disposed nearer the lower end of thebody, a piston valve element slideably mounted within the body andmovable to an upper position closing flow through the orifice and intothe pipe string and also movable to a lower position to uncover thecementing ports, said valve element having means coacting with saidtubular body to prevent flow through said orifice when said valveelement is moved to said position closing flow into the pipe string,releasable means for normally retaining the valve element in a positionintermediate the orifice and the equalizing openings in which positionthe cementing ports are covered and closed, said releasable means beingreleasable by a predetermined force applied to the valve element, theupper surface of said valve element being exposed to the pressure of thefluid flowing through the orifice and into the pipe when the valveelement is releasably retained in its intermediate position and thelower surface being exposed to the static pressure of the fluid in theannulus exteriorly of the body, whereby the valve element is subjectedto the pressure-differential forces on opposite sides thereof, saidreleasable retaining means being released either by the existence of apredetermined pressure-differential across said valve element which iscreated by a predetermined increase in velocity of flow through theorifice and into the pipe string in which event the valve element ismoved upwardly to close flow into the string or which is created by anincrease in pressure applied against the upper end of the valve elementthrough the pipe string in which event the valve element is moveddownwardly to uncover the cementing ports.

6. A fill-up and cementing device as set forth in claim 5, wherein aspring means is mounted within the body below the valve element andexerts its force to constantly urge the valve element toward its upperposition.

7. A fill-up and cementing device as set forth in claim 5, wherein thereleasable retaining means is a frangible shear pin having a strengthrelated to the size of the orifice, whereby a predetermined increase invelocity of flow through the orifice effects a predetermined increase inpressure-differential on opposite sides of the valve element which willfracture said shear pin.

8. A fill-up and cementing device as set forth in claim 5, wherein thereleasable retaining means is a frangible shear pin having a strengthrelated to the size of the orifice, whereby a predetermined increase invelocity of flow through the orifice effects a predetermined increase inCit pressure-differential on opposite sides of the valve element whichwill fracture said shear pin, and a spring means mounted in the bodybelow the valve element and exerting its force in a direction toconstantly urge the valve element upwardly.

9. A fill-up and cementing device as set forth in claim 5, together withan internal annular valve seat formed within the body spaced above theorifice, said valve element being generally cylindrical and having anannular valve sealing surface engageable with said valve seat when inits upper position, and sealing rings mounted on the upper portion ofthe valve element below the valve sealing surface and engageable withthe bore of the body to seal therewith.

10. A fill-up device including,

a tubular body having bottom closure means and having means forconnecting said body in a well pipe string,

said body having an orifice establishing communication between theexterior and interior thereof whereby fluid from the annulus surroundingthe body and pipe string may flow through the orifice and into thestring,

an internal annular valve seat formed within the body spaced above theorifice,

a piston valve element slidably mounted within the bore of the tubularbody and movable to an upper position closing flow in the pipe string,

said valve element being generally cylindrical and having an annularsealing surface engageable with said valve seat when in its upperposition,

sealing rings mounted on the upper portion of the valve element belowthe valve sealing surface and engageable with the bore of the body toseal therewith, said valve element having means coacting with saidtubular body to prevent flow through said orifice when said valveelement is moved to said position closing flow into the pipe string,

releasable means for normally holding said valve element in a loweredposition allowing flow through the orifice and into the pipe string,

said last-named means being releasable upon the application of apredetermined force against the valve element,

the upper surface of said valve element being exposed to the pressure ofthe fiuid flowing through the orifice and entering the string,

a predetermined increase in the velocity of the fluid flowing throughsaid orifice and into the pipe string resulting in a reduction in thepressure acting against the upper surface of said valve element, wherebythe pressure differential across said valve element creates the requiredforce to release the releasable holding means and to thereafter move theelement to an upper position closing further flow into the pipe string.

References Cited in the file of this patent UNITED STATES PATENTS2,033,563 Wells Mar. 10, 1936 2,698,054 Brown et al. Dec. 28, 19542,846,015 Pittman Aug. 5, 1958 2,847,074 Maly et a1 Aug. 12, 19582,874,785 Muse Feb. 24, 1959

5. A FILL-UP AND CEMENTING DEVICE INCLUDING, A TUBULAR BODY HAVINGBOTTOM CLOSURE MEANS AND HAVING MEANS FOR CONNECTING SAID BODY IN A WELLPIPE STRING, SAID BODY HAVING AN ORIFICE LOCATED NEARER ITS UPPER ENDAND ESTABLISHING COMMUNICATION BETWEEN THE ANNULUS OUTSIDE THE BODY ANDSTRING AND THE INTERIOR OF THE BODY AND STRING, SAID BODY HAVINGCEMENTING PORTS BELOW SAID ORIFICE AND HAVING EQUALIZING OPENINGS SPACEDBELOW SAID CEMENTING PORTS AND DISPOSED NEARER THE LOWER END OF THEBODY, A PISTON VALVE ELEMENT SLIDEABLY MOUNTED WITHIN THE BODY ANDMOVABLE TO AN UPPER POSITION CLOSING FLOW THROUGH THE ORIFICE AND INTOTHE PIPE STRING AND ALSO MOVABLE TO A LOWER POSITION TO UNCOVER THECEMENTING PORTS, SAID VALVE ELEMENT HAVING MEANS COACTING WITH SAIDTUBULAR BODY TO PREVENT FLOW THROUGH SAID ORIFICE WHEN SAID VALVEELEMENT IS MOVED TO SAID POSITION CLOSING FLOW INTO THE PIPE STRING,RELEASABLE MEANS FOR NORMALLY RETAINING THE VALVE ELEMENT IN A POSITIONINTERMEDIATE THE ORIFICE AND THE EQUALIZING OPENINGS IN WHICH POSITIONTHE CEMENTING PORTS ARE COVERED AND CLOSED, SAID RELEASABLE MEANS BEINGRELEASABLE BY A PREDETERMINED FORCE APPLIED TO THE VALVE ELEMENT, THEUPPER SURFACE OF SAID VALVE ELEMENT BEING EXPOSED TO THE PRESSURE OF THEFLUID FLOWING THROUGH THE ORIFICE AND INTO THE PIPE WHEN THE VALVEELEMENT IS RELEASABLY RETAINED IN ITS INTERMEDIATE POSITION AND THELOWER SURFACE BEING EXPOSED TO THE STATIC PRESSURE OF THE FLUID IN THEANNULUS EXTERIORLY OF THE BODY, WHEREBY THE VALVE ELEMENT IS SUBJECTEDTO THE PRESSURE-DIFFERENTIAL FORCES ON OPPOSITE SIDES THEREOF, SAIDRELEASABLE RETAINING MEANS BEING RELEASED EITHER BY THE EXISTENCE OF APREDETERMINED PRESSURE-DIFFERENTIAL ACROSS SAID VALVE ELEMENT WHICH ISCREATED BY A PREDETERMINED INCREASE IN VELOCITY OF FLOW THROUGH THEORIFICE AND INTO THE PIPE STRING IN WHICH EVENT THE VALVE ELEMENT ISMOVED UPWARDLY TO CLOSE FLOW INTO THE STRING OR WHICH IS CREATED BY ANINCREASE IN PRESSURE APPLIED AGAINST THE UPPER END OF THE VALVE ELEMENTTHROUGH THE PIPE STRING IN WHICH EVENT THE VALVE ELEMENT IS MOVEDDOWNWARDLY TO UNCOVER THE CEMENTING PORTS.